Gettin' rid of BlurFilter

this is the code i used:

[AS]import flash.filters.BlurFilter;
var Blur:BlurFilter = new BlurFilter(5, 5, 3);
var unBlur:BlurFilter = new BlurFilter(0, 0, 0);
greenbtn.onPress = function() {
greenbg.filters = [Blur];
greenbtn2.onPress = function() {
greenbg.filters = [unBlur];

problem is, when i unblur it, the whole movie felt laggy, i think it’s because the blur effect stays within the greenbg.

i thnk i’m sorta like faking it by using the AS above, how do i just get rid of the blur effect?

any ideas?